1. Field of the Invention
This invention pertains to a cylinder head configuration, valves having an extended head height for use with the cylinder head, the cylinder head being internally configured to accept these valves. The cylinder head and the intake and exhaust valve configurations are for use with flathead engines. The combustion chamber shape and gas flow through the combustion chamber of the cylinder head results in an increase of combustion efficiency, a reduction of hydrocarbon emissions and an increase in compression ratio.
2. Description of the Related Art
It is known to provide four cycle engines with side valve, "L-head" or flathead type cylinder heads with integral combustion chambers, hereinafter "flathead" engines. These engines do not have valves opposite the top surface of the piston, but instead, have the valves adjacent the piston. The flathead engine has a head with a cavity formed in it. This cavity provides the combustion chamber for the engine.
A combustible fluid, such as a mixture of air and fuel, is directed to the combustion chamber through an intake valve. An exhaust valve allows spent gasses through a passage to an exhaust manifold, thus the exhaust is evacuated from the combustion chamber.
The flathead engine was in widespread use through the 1950's, including automotive use, but has been superceded in many applications by overhead valve engines. The flathead engine continues to be widely used in small displacement four cycle engines having one or two cylinders. Typical applications for four cycle flathead engines are found in gas operated lawn mowers, electric generator power systems, snowblowers, weed trimmers, lawn edgers, go kart motors, boat engines and the like.
There have been many intake/exhaust/valve configurations in the development of the flathead engine. Many of these valve configurations use slide valves, shuttle valves or poppet valves.
For instance, a flathead engine with a poppet valve configuration is shown in U.S. Pat. No. 1,784,555. A slide type valve, a piston type valve and a sleeve type valve are shown in U.S. Pat. Nos. 1,856,348; 1,680,099 and 1,922,678. None of these patents show the valve configuration presented herein.
The age of these patents and the paucity of modern day patents concerning valve systems for flathead engines show that there has been a dearth in the generation of ideas relating to flathead engines. This invention is directed to a system that makes the four cycle flathead engine more competitive with the overhead valve and overhead camshaft engines in vogue and being developed today. The overhead valve engines are more expensive to produce than the flat engine and there are great advantages in production economics if an improvement can be made in the efficiency and especially in reducing hydrocarbon emissions of the flathead engine.
One advantage of this invention is that hydrocarbon emissions are reduced to the point where small engine manufacturers can produce a clean burning engine without having to resort to an overhead valve configuration to get equivalent hydrocarbon emissions.